Effect of Snacks on Aging

The purpose of this study is to determine if daily consumption of 2 oz of pecans compared to 3.5 oz pretzel snacks for 12 weeks will 1) contribute to the body's ability to protect itself from oxidative damage (caused by oxygen radicals created by ultraviolet (UV) B light) by evaluating skin resistance to UV light irritation, skin fats/oils degradation and "rusting", and oxidative damage to the skin genes; and 2) explore the mechanisms of how snack consumption may affect aging by analyzing blood markers of aging as well as the microbes living in the gut (gut microbiome).

Oxidative stress plays a significant role in the aging process. Antioxidant potential of tree nuts, including pecans, has been previously reported. However, very few studies have evaluated the antioxidant effects and their underlying mechanisms of nut consumption in the aging population. Skin is the largest organ and is the first body part to exhibit signs of aging. Human skin exposed to solar ultraviolet radiation (UVR) experiences a dramatic increase in production of reactive oxygen species (ROS) and inflammation. Moreover, skin aging is associated with increased levels of oxidative stress. Investigators previously showed that almond and pomegranate consumption can improve the antioxidant defense of skin by reducing UV-induced damage. In addition, the prebiotic properties of nuts and other bioactive-rich foods have been of great interest lately, current study team and others have reported the gut microbiome modulating effects of tree nut consumption. Based on this evidence and other published data, it is being proposed that pecans, due to their bioactive compound content, may have the potential to contribute to whole body antioxidant protection, modulate the gut microbiome and affect the aging process. The aim of this study is to evaluate the effects of incorporating 2 oz of pecans into diet compared to isocaloric pretzel snacks daily for 12 weeks 1) on whole body antioxidant capacity by evaluating skin resistance to UV irritation, lipid oxidation, and oxidative DNA damage; and 2) explore the mechanism of how pecan consumption affects aging by analyzing circulating biomarkers of aging as well as the gut microbiome. This will be a two-arm, randomized, placebo-controlled intervention study in 60 middle-aged and older generally healthy non-vegetarian/vegan women (age 55-75 years, Fitzpatrick's skin types II-IV). Investigating the effects of pecan consumption on skin antioxidant defense and systemic oxidative status will uncover valuable new insights into whether bioactive compounds in pecans can contribute to the total body antioxidant capacity and affect the aging process.